Don't believe headlines that make broad health claims about a single food. This is why:

You've definitely seen the headlines announcing that eating blueberries lowers your chance of dementia, or that red wine is beneficial for your heart, or that coffee prevents type 2 diabetes – or any of the other major health claims for a particular "superfood." What, however, is the truth behind these claims?

While we, as a group of nutritional scientists, have been participating in this type of research, the headlines are not our responsibility. However, beneath those headline-grabbing stories lies vital and serious science that will help us all live happier and healthier lives.

We investigate bioactive components in foods that have a health impact (either good or bad). Bioactives, such as specific fatty acids, fiber, or flavanols (a group of molecules found in tea or apples), are not needed for survival, yet they nonetheless have an impact on human health.

Separating the effect of a food from an individual chemical is a major difficulty in bioactives research (foods are incredibly complex and contain many compounds). In a cup of coffee, there are certain phenolic acids that are good for your heart, but there are also other components that can raise your cholesterol. This complicates – but also excite – our research.

To understand what is happening and eventually provide more confidence in the advice we provide, we must find strategies to discriminate between the health effects of different elements of diets.

Comparing people with varied diets and following them for a long time is one technique to learn more about the effect of individual foods on health. This method has assisted us in demonstrating that the Mediterranean – and Nordic – diets keep us healthier for longer periods of time. When we wish to learn more about certain foods or their components, however, this technique is faulty.

Foods are never consumed in isolation, and dissecting this in such studies is extremely challenging. To make the conclusions of such study more understandable, they are frequently translated into culinary equivalents, such as the notorious punnet of raspberries, cups of tea, or bottles of wine that you should consume for good health. In actuality, there's a lot more difficult.

Diet and health research is tough since there are so many variables to examine. There are some nutrients that humans require in order to live. Dietary patterns can have an impact on general health and are the basis for recommendations like the Eatwell guidance from the UK government.

Then there are bioactive chemicals, which are mostly present in plant foods and may have a health-promoting effect.

Bioactives research frequently results in sensationalized food stories. In truth, it is only a small part of the diet, and it may be found in other places as well. Blueberries are a good example. They are rich in bioactives, but they are also costly. Blackberries and plums have the same bioactives as blueberries but are far less expensive.

We've learned a lot about the chemicals found naturally in foods over the last few decades, including what they are and how they influence the body. Some of them have heart, brain, and gut health benefits, allowing us to sprint faster, bike longer, concentrate harder, and relax more readily.

Put a premium on variety.

However, when ingested in large quantities, several of them might create issues. Green tea flavanols, for example, can harm the liver if ingested in big quantities. We're only now beginning to figure out if there's a magic number of these compounds to get the best results. Until then, a well-balanced diet is the best course of action.

The beautiful thing about our knowledge of nutrition is that it is constantly evolving and improving, and as study advances, we are learning more about what foods to avoid.

Everyone should develop a diet portfolio that includes the essential nutrients, fiber, and bioactives required to stay healthy and age gracefully. Our bodies are highly complex, and we require a wide range of vitamins, minerals, macro and micronutrients to function properly. It appears that bioactives will need to be added to this list. But it makes no difference where they come from; what matters is variety.

You should be careful of dietary advice that advocates avoiding a wide variety of delicious foods in favor of a few "superfoods" that appear to have magical characteristics. Nutrition is far more complicated than that — and maintaining a balanced diet is far simpler.